Factsheets - Sheep & BeefThe following fact sheets have been prepared by Anexa FVC Veterinarians as a guide to topics of interest. For specific information please contact your local vet.

Are your sheep ready for mating?

By Lucy Scott, Veterinarian, Anexa Vets, Raglan

As hogget and ewe mating is coming up fast, there a few essential things to ensure maximum performance in ewes and hoggets. Keep potential stressors low, and feed ewes as well as possible at this time of the year to get the best scanning and lambing percentages.

Mating hoggets is a great way to increase lambs on the ground, speed up your genetic gains, and increase the lifetime performance of your ewes, but it must be done well. If not, then the opposite can occur, and lifetime performance is reduced.

The best way to ensure your ewes are ovulating well when the time comes, is to body condition score. Aim for a body condition score over 3 all year round, and remember - lamb survival falls by 5% for every 0.5 BCS lost between scanning and lambing.

If you do decide to breed your hoggets, then a minimum weight of 40kg should be used when determining if they are ready for the ram. Preferentially feeding light ewes and hoggets in the lead up to mating will pay off in the long run, and so will feeding them well during pregnancy.

Vasectomised rams (teasers) will increase early lambs born in ewes by synchronising them and increase ovulation rate in hoggets by helping to bring them on heat. Rams should be given time to heal before being used and can still have fertile semen 6-8 weeks after surgery. In the ewes, teasers should be put out 18-21 days before the ram but in hoggets they should be put out just 17 days before. A ram ratio of 1:50 in hoggets will increase pregnancy rates as hoggets are shy breeders.

Rams should have a soundness exam several months before mating to ensure they are fit for purpose. Brucella ovis is often what we are looking for when we palpate rams but any condition that causes a fever or increased testicular temperature in a ram will reduce its fertility for up to 90 days.

Mating is a multifactorial event and getting it right sets your flock up for the entire season, so if you would like to discuss the incremental things that could increase this year’s scanning percentage let us know; we are here to help.

Vaccinations:

Toxoplasmosis vaccinations to first time breeders should be done a minimum of four weeks before the ram or teaser is put out. Toxoplasmosis is a live vaccine so care should be taken to keep the vaccine cold and only needs to be given to a sheep once to provide life-long protection. Vaccination with Toxovax increases lambing percentage by an average of 3% and decreases the incidence of dry ewes by an average of 14%. 100% of New Zealand sheep farms have been found to have Toxoplasmosis present, and can cause sporadic early abortions, birth of weak lambs and large-scale abortion storms so this is a vaccine worth spending your money on.

Campylobacter boosters for ewes should be completed prior to mating, and first-time breeders need 2 injections 4 to 8 weeks apart before planned start of mating. This vaccine does not give lifelong immunity which is why a booster is recommended yearly. 88% of farms have campylobacter on farm and 50% of mixed age ewes are exposed during their lifetime, and infection of naïve ewes can cause dramatic abortion storms or decreased scanning/lambing percentages.

Androvax is a performance vaccine that increases ovulation rate and therefore lambing percentage by an average of 20%. It requires strategic planning, as if used, management strategies must be in place to ensure sufficient feed for the increased number of lambs, and the increased number of ewes rearing multiples. Scanning would be essential to ensure preferential treatment of multiple bearing ewes.